In recent years, in a vehicle provided with an internal combustion engine, a kinetic energy of vehicle is regenerated by converting the kinetic energy into an electrical energy by an alternator when an internal combustion engine is decelerated in a fuel cut. The recovered electrical energy is charged in a battery.
However, when the vehicle is decelerated and a throttle valve is closed so that an intake air pressure is decreased, a pumping loss of the internal combustion engine is increased. Corresponding to this pumping loss, an energy loss is increased and an energy-regenerate efficiency is deteriorated.
To solve the above issue, as shown in JP-H-8-100689A, in a system having an EGR apparatus for recalculating a part of an exhaust gas into an intake pipe, an EGR valve is opened to recalculate an EGR gas into the intake pipe to decrease an intake air pressure when the vehicle is decelerated. Thereby, the pumping loss of the internal combustion engine is decreased, and the energy-regenerate efficiency is improved.
However, even if the EGR valve is opened when the vehicle is decelerated in fuel-cut, the pumping loss can not be decreased enough and the energy-regenerate efficiency is not sufficiently improved.